PURPOSE: To hold a core surely in a prescribed position in a casting mold by detaining the core print parts formed to the core to a fixing means provided to the mold and energizing the core in a prescribed direction.

CONSTITUTION: A sliding member 5 is slided in a direction B against the energizing of a spring by a pressing means to position pins 4 for fixing a core in the prescribed position in the stationary mold 1a of a casting mold 1. On the other hand, the core print parts 2' of a core 2 are fitted into the holes 1' for the core print parts of the mold 1a. When the pressing means is removed, the member 5 is slided in the direction A through energizing of the spring, by which the pins 4 are thrusted into the recesses 2'a of the parts 2'. Further, the parts 2' are moved in the same direction through sliding of the member 5 in the direction A. Therefore, the parts 2' are pressed toward the side walls of the holes 1' and the core 2 is fixed firmly to the mold 1a. As a result, the core 2 is held surely in the prescribed position in the mold 1.